Multi-digit glow indicator tube

ABSTRACT

The disclosure is of a matrix-type glow indicator tube capable of displaying a number of three figures. The indicator tube includes three groups of separate and distinct cathode elements, each group making up a figure eight. Three transverse cathode elements of each group are disposed on the top surface of an insulating plate having apertures extending therethrough, so that they extend transversely over their associated aperture. Each group also includes four longitudinal cathode elements which are disposed on the bottom surface of the insulating plate, so that they extend longitudinally under their associated aperture. An anode element is provided for each group of the cathode elements and lies in the same stratum as the longitudinal cathode elements. The anode element is positioned between the longitudinal cathode elements and extends parallel thereto. In this construction, the cathode elements of each group are energized in different combinations to provide representation of numerals zero to nine.

United States Patent [191 Kunii et al.

l l MULTI-DIGIT GLOW INDICATOR TUBE [75] Inventors: Takao Kunii; Teruaki Tanaka;

Sadaaki Kanaya; Shuichi Nagayama, all of Osaka, Japan [73] Assignee: Matsushita Electronics Corporation,

Kadoma City, Osaka, Japan [22] Filed: July 20, 19 72 21 Appl.No.:273,492

[30] Foreign Application Priority Data 1 June 25, 1974 2/1972 Tagawa ..3l3/l09.5 3/1972 Janning ..313/109.5

Primary ExaminerPalmer'C. Demeo [5 7] ABSTRACT The disclosure is of a matrix-type glow indicator tube capable of displaying a number of three figures. The indicator tube includes three groups of separate and distinct cathode elements, each group making up a figure eight. Three transverse cathode elements of each group are disposed on the top surface of an insulating plate having apertures extending therethrough, so that they extend transversely over their associated aperture. Each group also includes four longitudinal cath- -ode elements which are disposed on the bottom surface of the insulating plate, so that they extend longitudinally under their associated aperture. An anode element is provided for each group of the cathode elements and lies in the same stratum as the longitudinal cathode elements. The anode element is positioned between the longitudinal cathode elements and extends parallel thereto. In this construction, the cathode elements of each group are energized in different combinations to provide representation of numerals zero to nine.

3 Claims, 8 Drawing Figures l 35 2% 1 1 K4 8, 72 A1 PATENTEDJUHZS mm SHEEI 1 [If 4 Fig.

m T TR MULTI-DIGIT GLOW INDICATOR TUBE This invention relates to a multi-digit glow indicator tube and a method of fabricating the same.

There are many types of cheracter display devices presently available, and one is a matrix-type glow indicator tube that is capable of providing representation of numerals zero to nine. Tubes of this type include a plurality of groups of cathode-anode assemblies, the cathode and anode of each assembly being positioned to face each other so as to exhibit cathode glow when energized. The cathodes may be elongated metallic elements which are arranged in the same stratum to form a figure eight and connected in different combinations so that each combination provides a different numeral representation. However, these tubes have a constructional disadvantage that the illuminated numerals are rather illegible because the elongated elements are required to be suitably spaced from each other so as to be separately operated for glow discharge.

Another type of known glow indicator tube includes a stack of ten filaments acting as cathodes, each of which is formed to make up one of the numerals zero to nine. Perhaps the most serious limitation of tubes of this type is that the multiple-layer construction makes the assembly operation undesirably and intolerably complicated.

The objects of the present invention are directed toward the provision of an improved matrix-type glow indicator tube which is compact and relatively simple in construction and operation.

Briefly, an indicator tube embodying the invention includes three groups of separate and distinct cathode elements, each group making up a figure eight. Three transverse cathode elements of each group are disposed on the top surface of an insulating plate having apertures therethrough, so that they extend transversely over their associated aperture. Each group also includes four longitudinal cathode elements which are disposed on the bottom surface of the insulating plate, so that they extend longitudinally under their associated aperture. An anode element is provided for each group of the cathode elements and lies in the same stratum as the longitudinal cathode elements. The anode element is positioned between the longitudinal cathode elements and extends parallel thereto. With this arrangement, the cathode elements of each group are energized in different combinations to provide representation of numerals zero to nine. One advantage of this construction lies in the fact that precausions need not be taken to prevent the anode elements from obstructing the cathode elements.

The invention is described in greater detail by reference to the drawings wherein:

FIG. 1 is a sectional view of one embodiment of the invention;

FIG. 2 is a plan view of an insulating member used as upper, intermediate and lower insulating plates in the device of FIG. 1;

FIG. 3 is a plan view of a lower metal plate employed in the device of FIG. 1;

FIG. 4 is a plan view of an upper metal plate employed in the device of FIG. 1;

FIG. 5 is a plan view of a mask plate employed in the device of FIG. 1;

FIG. 6 is a fragmentary exploded view of the device shown in FIG. 1;

FIG. 7 is a front elevational view of the device shown in FIG. 1; and

FIG. 8 is a perspective view of the device shown in FIG. 1, its cover being disassembled from a board.

The principles of the present invention may be employed with various types of character display tubes, but the invention is described as it applies to a glow indicator tube capable of displaying a number of three figures.

Referring now to FIG. 1, a glow indicator tube 10, embodying the invention, includes a stem 11 having a generally rectangular base 12, on which base is supportd the electrode assembly of the tube 10 to be described in great detail below. The stem 11 is of insulating material and its base includes top and bottom surfaces 13 and 14, respectively, and carries a conventional tubulation 15, by means of which the tube 10 may be exhausted and filled with gas.

A lower insulating member 16, the plan view of which is shown in FIG. 2, comprises a plate of ceramic or mica and is disposed on the base 12, with the bottom surface thereof in contact with the top surface 13 of base 12. As shown, the insulating plate 16 has generally rectangular apertures 17, 18 and 19 extending therethrough parallel to each other, each aperture corresponding to one of the three digits of a number to be displayed. The shape and size of each aperture l7, l8 and 19 is such as to encompass onedigit and, in the illustrated embodiment, each aperture is formed to lean somewhat to the right. The insulating plate 16 also has small apertures 20, 21 and 22 extending therethrough,

each of which is of circular shape and is positioned at the lower right-hand side of its associated rectangular apertures 17, 18 and 19 to display a decimal point, if desired.

A lower metal plate 25, the plan view of which is shown in FIG. 3, is disposed on the surface of the insulating plate 16 opposite to the base 12. The metal plate 25 comprises a plurality of elongated electrode portions extending inwardly from frame portions 30 and 31, the electrode portions being in three groups A, B and C. Each group corresponds to one of the three digits making up the number. With respect to the group A, there are longitudinal cathodes 32 and 33 spaced apart but axially aligned, longitudinal cathodes 34 and 35 spaced apart but axially aligned parallel to cathodes 32 and 33, and a central anode 36 extending from the frame portions 30 to 31. The central anode 36 has a portion 37 of greater width formed substantially centrally thereof for promoting cathode glow. Group A also includes another anode 38 positioned at the righthand side of cathode 35, which anode is used to display a decimal point. Referring back to FIG. 1, in disposing the lower metal plate 25 on the lower insulating plate 16, care must be taken to insure that the regions of glow of the longitudinal cathodes, indicated by the hatching 39, and the wide portion 37 of central anode 36 overlie their associated aperture of the lower insulating plate 16.

An intermediate insulating plate 41, which is identical to the lower insulating plate 16 shown in FIG. 2, is disposed on the top surface of the lower metal plate 25, with theirv apertures aligned with the apertures 17, 18 and 19 of the lower insulating plate 16.

Then, an upper metal plate 42, the plan view of which is shown in FIG. 4, is disposed on the top surface of the intermediate insulating plate 41. As shown, the

upper metal plate 42 comprises four elongated cathode portions 43, 44, 45 and 46, allbeing parallel to each other and substantially transverse to frame portions 47 and 48. The transverse cathodes 43 to 46 each have three regions of glow, indicated by hatching 50, which are adapted to be actuated by the anodes 36 and 38 of the lower metal plate 25 to exhibit cathode glow. Thus, it is essential that the thickness of the intermediate insulating plate 41 is such as to keep the lower and upper metal plates 25 and 42 away from each other by a distance appropriate for causing the cathodes 43 to 46 to glow. Further, since the lower transverse cathode 46 is used to display decimal points, it is important that the upper metal plate 42 be placed on the intermediate insulating plate 41, with the lower cathode electrode 46 extending over the three small apertures 20, 21 and 22 of the insulating plate 41.

Referring again to FIG. 1, an upper insulating plate 52, which is identical to the lower and intermediate insulating plates 16 and 41 shown in FIG. 2, is disposed on the top surface of the upper metal plate 42, with the three apertures thereof aligned with their corresponding apertures l7, l8 and 19 of the insulating plates 16 and 41. The upper insulating plate 52 is used as a spacer between the upper metal plate 42 and a mask plate 53 which is disposed on the insulating plate 52, as is best shown in FIG. I.

In FIG. 5, the mask plate 53 is of metallic material and includes a plurality of elongated apertures or slits in three groups A, B and C, the slits of each group being arranged in the form of a figure eight. The mask plate 53 may be of opaque, insulating material rather than metallic material. In group A, slits 55 and 56 are spaced apart but axially aligned and slits 57 and 58 are spaced apart but axially aligned parallel to slits 55 and 56. Slits 59, 60 and 61 are all parallel to each other and are substantially transverse to the other slits, with slits 59 and 61 at the top and bottom of the figure eight and slit 60 at the center of the figure eight. All of the slits are distinct and separate from each other. A small aperture 62 of circular shape is also formed in the mask plate 53 at the lower right-hand side of its corresponding slits 55 to 61 to display decimal points.

Referring to FIG. 6, the disposition of the mask plate 53 is such that the seven slits 55 through 61 and one aperture 62 overlie their corresponding glow regions of the cathode electrodes of lower and upper metal plates 25 and 42. The slits 55 through 61 is of somewhat greater width than the glow regions of cathode electrodes, and in the operating tube, cathode glow is visible through the slits.

Referring again to FIG. 1, after the electrode assembly of the tube is arranged on the stem 11 in the manner described above, the frame portions 30 and31 of the lower metal plate 25, and the frame portions 47 and 48 of the upper metal plate 42 are removed so that the cathode and anode elements are separate from each other. Then, a face plate'65 is disposed on the electrode assembly of the tube 10 and is hermetically sealed to the stem 11 by means of any suitable sealing members or materials 66. The face plate 65 is of lighttransmitting material, so that light generated in the inthrough the tubulation l5. Thereafter, the tubulaion 15 is sealed off in a conventional manner.

Electrical connections are made to the cathode and anode elements so that they are used in different combinations to provide the various desired numeral representations. For example, the cathode 32 and 33 or 34 and 35 are used to represent numeral one, cathodes 43, 34, 44, 33 and 45 are used to represent numeral two, cathodes 43, 34, 44, 35 and 45 are used to represent numeral three, and so forth. To this end, in the illustrated embodiment, each corresponding cathode element 32 of groups A, B and C is connected together to a common lead-out wire leading to a terminal K,, and each corresponding cathode element 34 is connected together to a common lead-out wire 71 leading to a terminal K Further, each corresponding cathode 33 is connected together to a common lead-out wire 72 leading to a terminal K and each corresponding cath-- ode 35 is connected together to a common lead-out wire 73 leading to a terminal K,. The cathode element 43 of the upper metal plate 42 is connected to a terminal K through a wire 74, the cathode element 44 is connected to a terminal K; through a wire 75, and the cathode element 45 is connected to a terminal K through a wire 76. The remaining cathode element 46 is connected to a terminal K through a wire 77. On the other hand, as is best seen in FIG. 6, the central anode element 36 and the anode element 38 of group A are connected to a terminal A and the anode elements of each group B and C are also connected to terminals A and A;,, respectively.

The glow indicator tube of this type is usually operated by a known division circuit. For example, where it is desired for the tube 10 to display numeral thirty, a negative potential is applied to terminals K K K K and K and a positive potential is applied to A causing the cathode elements 34, 35, 43, 44 and 45 of group B to glow, thereby to represent the tenth digit three. Simultaneously, a negative potential is applied to K K K K K and K and a positive potential is applied to A so that the cathode elements 32, 34, 33, 35, 43 and 45 of group A are caused to glow, thereby producing the unit digit zero. Further, in order to display a decimal point, a negative potential is applied to K and a positive potential is applied to A,. If the mask plate 53 is of metallic material, it would be advantageous for the plate to be connected to a positive potential of less than 70 percent of that applied to the anode elements, since the mask plate 53 acts as a trap for cathode material which sputters from the cathode elements and otherwise deposits on' the face plate 65 of the tube 10. Another advantage of such potential applied to the mask plate 53 lies in the fact that a shield effect is obtained among the three digits of a number to bedisplayed.

FIGS. 7 and 8 illustrate the manner is which the tube 10 of the invention is mounted on a board 80. As is best shown in FIG. 7, the board includes a central opening in which a cap 81 for protecting the tubulation 15 already sealed is inserted and extends downwardly, with flanges 82 of cap 81 in contact with the top surface of the board 80. The tube 10 is placed on the flanges 82 of the cap 81, and then a cover 83 having a window 84, best shown in FIG. 8, is disposed on the tube 10, so that the numeral displaying portion of the tube 10 is visible through the window 84. Securing the cover 83 to the board 80 may be made by inserting lugs 85 formed in the cover 83, into their associated apertures 86 and thereafter bending the lugs inwardly or outwardly on the bottom surface of the board 80.

In this embodiment of the invention, the cathode and anode elements, which are in the form of narrow strips extending from the side walls of the tube 10, are bent downwardly to extend to the top surface of the board 80, on which surface their electrical connections to terminals K through K and A through A are made by providing layers 90 of metallic material on the surface. The conductive coatings 90 may be painted, sprayed, or otherwise applied to the top and bottom surfaces of the board 80.

The present invention provides a multidigit glow indicator tube which has many advantages over similar devices in the prior art. One advantage lies in the compactness and simplicity in construction and operation of the tube of the invention. In addition, the multi-layer construction of the invention and the simplicity of the cathode and anode electrodes facilitate assembly and make automatic assembly of the tube a practicality. Since the board 80, on which the tube 10 of the invention is secured, has the pre-formed and programmed conductive coatings 90 thereon, complex external writing operations are not required to operate the tube. Further, the board serves to increase the mechanical strength of the entire device and acts as a terminal board.

Although the present invention has been described with referrence to an indicator tube emplying a figure eight as a matrix of cathode electrodes, it should be understood that many modifications of the fundamental character in matrix form may be made.

What is claimed is:

I. A glow indicator tube which comprises:

a gas containing envelope having a transparent face plate;

a first electrode assembly supported within said envelope and consisting of a plurality of narrow strip anode electrodes and a plurality of narrow strip cathodes with glow regions which all extend in a first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, each group consisting of a pair of two cathode electrodes disposed in face to face relationship and spaced apart, one anode electrode disposed between said cathode electrodes, and a short electrode disposed adjacent one of said cathodes for displaying a decimal point respectively; second electrode assembly supported within said envelope and having a plurality of narrow strip cathode electrodes with glow regions which all extend in a second direction transverse to the first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, when combined together with the first frame;

a plurality of insulating plates inserted between said first and second electrode assemblies and said envelope and having a plurality of substantially rectangular and circular openings corresponding to said number of digits and decimal digits to be displayed respectively, and i a mask plate inserted between said one of insulating plates and one side of said envelope and having a plurality of openings therethrough, each opening corresponding to each group of vertical and horizontal electrode matrix arrays.

2. A glow indicator tube according to claim 1, wherein said mask plate is made of a metal so as to effectively promote the glow discharge lower voltage as well as to produce a shield effect among the digits.

3. In a glow indicator tube having a gas containing envelope with a base, a transparent face plate in spaced relationship to this base and an electrode assembly of the tube disposed between the base and the face plate, the electrode assembly comprising:

A. A first electrical insulating means disposed between the base and a first electrode means, said means having a plurality of narrow strip anode electrodes and a plurality of narrow strip cathodes with glow regions which all extend in a first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, each group consisting of a pair of two cathode electrodes disposed in face to face relationship and spaced apart, one anode electrode disposed between said cathode electrodes, and a short electrode disposed adjacent one of said cathodes for displaying a decimal point respectively, and each of said strip cathodes and said strip anode are disposed to lie generally in the same plane;

E. Second electrical insulating means disposed between said first electrode means and a second electrode means, said second electrode means having a plurality of narrow strip cathode electrodes with glow regions which all extend in a second direction transverse to the first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, when combined together with the first electrode means; and

C. A third electrical insulating means disposed between said second electrode means and a mask plate and positioning said mask plate adjacent the face plate of the tube, each of said insulating means having a plurality of substantially rectangular and circular openings corresponding to said number of digits and decimal digits to be displayed respectively, and said openings are in alignment and are located in the glow regions of said first and second electrode means, said mask plate having a plurality of groups of openings disposed in spaced apart relationship, and corresponding to the number of digits and decimal points to be displayed, a first set of said openings being respectively aligned with said pairs of two cathodes of said first electrode means, a second set of said openings being respectively aligned with said cathode electrodes of said second electrode means and a single opening of each group of openings being aligned with an associated short electrode of said first electrode means.

I UNITED STATES PA TENT OFFICE CERTIFICATE OF CORRECTION- Patent No. $819,975 Dated June 25, 197

Inventor(s) Takao Kunii. et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In claim 1, column 5, line 61, the word "circular" should be "other" In claim 5, column 6, line 46, the word "circular" should be "other" Signed and sealed this 24th day of September 1974,

(SEAL) Attest:

MCCOY M. GIBSON JR. c. MARSHALL DANN Attesting Officer Commissioner of Patents USCOMM-DC 6037 B-PGQ u.s. GOVERNMENT PRINTING OFFICE I! o-:l6-s34.

FORM PO-105O (10-69) 

1. A glow indicator tube which comprises: a gas containing envelope having a transparent face plate; a first electrode assembly supported within said envelope and consisting of a plurality of narrow strip anode electrodes and a plurality of narrow strip cathodes with glow regions which all extend in a first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, each group consisting of a pair of two cathode electrodes disposed in face to face relationship and spaced apart, one anode electrode disposed between said cathode electrodes, and a short electrode disposed adjacent one of said cathodes for displaying a decimal point respectively; a second electrode assembly supported within said envelope and having a plurality of narrow strip cathode electrodes with glow regions which all extend in a second direction transverse to the first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, when combined together with the first frame; a plurality of insulating plates inserted between said first and second electrode assemblies and said envelope and having a plurality of substantially rectangular and circular openings corresponding to said number of digits and decimal digits to be displayed respectively, and a mask plate inserted between said one of insulating plates and one side of said envelope and having a plurality of openings therethrough, each opening corresponding to each group of vertical and horizontal electrode matrix arrays.
 2. A glow indicator tube according to claim 1, wherein said mask plate is made of a metal so as to effectively promote the glow discharge lower voltage as well as to produce a shield effect among the digits.
 3. In a glow indicator tube having a gas containing envelope with a base, a transparent face plate in spaced relationship to this base and an electrode assembly of the tube disposed between the base and the face plate, the electrode assembly comprising: A. A first electrical insulating means disposed between the base and a first electrode means, said means having a plurality of narrow strip anode electrodes and a plurality of narrow strip cathodes with glow regions which all extend in a first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, each group consisting of a pair of two cathode electrodes disposed in face to face relationship and spaced apart, one anode electrode disposeD between said cathode electrodes, and a short electrode disposed adjacent one of said cathodes for displaying a decimal point respectively, and each of said strip cathodes and said strip anode are disposed to lie generally in the same plane; B. Second electrical insulating means disposed between said first electrode means and a second electrode means, said second electrode means having a plurality of narrow strip cathode electrodes with glow regions which all extend in a second direction transverse to the first direction and forming predetermined groups of electrodes corresponding to number of digits to be displayed, when combined together with the first electrode means; and C. A third electrical insulating means disposed between said second electrode means and a mask plate and positioning said mask plate adjacent the face plate of the tube, each of said insulating means having a plurality of substantially rectangular and circular openings corresponding to said number of digits and decimal digits to be displayed respectively, and said openings are in alignment and are located in the glow regions of said first and second electrode means, said mask plate having a plurality of groups of openings disposed in spaced apart relationship, and corresponding to the number of digits and decimal points to be displayed, a first set of said openings being respectively aligned with said pairs of two cathodes of said first electrode means, a second set of said openings being respectively aligned with said cathode electrodes of said second electrode means and a single opening of each group of openings being aligned with an associated short electrode of said first electrode means. 